Fix Lightning Potential Index calculation failure

[weiwangncar]

TYPE: bug fix

KEYWORDS: LPI, malloc error, NaNs

SOURCE: internal

DESCRIPTION OF CHANGES:
Problem:
The model stops right away with malloc error (with gfortran) when using lightning_option = 3, the option to compute lightning potential index (the problem occurred only with a 2 domain test). The error is due to variable packaging for this option. Once this error is fixed, the model can run but produces NaNs in the diagnostics. Array for hail mixing ratio is removed from the call as well, as it is not used.

Solution:
Add additional variables for packaging, and limit hydrometeors to a number that is not smaller than 1.e-10, which eliminates the NaNs.

LIST OF MODIFIED FILES:
M Registry/Registry.EM_COMMON
M phys/module_lightning_driver.F
M phys/module_ltng_lpi.F

TESTS CONDUCTED:

1. The model ran with 2 domain test, and do not produce NaNs.
2. The Jenkins tests are all passing.

RELEASE NOTE: Fixed a bug for lightning diagnostic option 3, an option for lightning potential index calculation. The bug prevented nested case to run, and may produce NaNs in the diagnostics.

[dudhia]

Makes sense. Thanks for tracking it down.

[weiwangncar]

The Jenkins test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None

[dudhia]

When you say it produces NaNs in the diagnostics, is that still the case after the fix? It was not clear.

[weiwangncar]

@dudhia Added more in 'Solution'.